Preliminary studies on the relation between the audio-visual cues' perception and the approaching speed of electric vehicles

For decades, quiet and zero emission vehicles have been considered the challenge for researchers and for the industry. Today, despite the great results obtained in the fields of air and noise pollution, the electric vehicles (EV) and hybrid electric vehicles (HEV) have raise an important question regarding the pedestrian safety. At the speeds permitted in urban areas (< 50 km/h) these vehicles are considerably quieter than the traditional ones powered by gasoline or diesel. Nevertheless the amount of auditory cues associated to the approaching of these vehicles can be reduced. This can determine an increase of the risk of accidents for the pedestrians. Even though the recent studies on this problem are focused, mainly, on the minimum sound levels and on the spectral content of the approaching vehicles, further aspects of the semantic content's change of the event should be considered. In this paper a preliminary investigation on the relationship, and possible incoherence, among the approaching speed of the vehicles, the auditory cues and the semantic content was performed, and results are presented. For the investigation, an immersive virtual reality environment was used.